Keshoff



(No Model.)

WN. G. HBRRESHOFP. I STEAM ENGINBVALVB. Y l" No. 280,312. Patented June 26, 1883. Y

fly.. y////////////////////// 4 UNITED STATES PATENT OFFICE.

N ATHANIEL G. HERRESHOFF, OF BRISTOL, RHODE ISLAND, ASSIGNO-B= TO THE HERRESHOFF MANUFACTURING COMPANY, OF RHODE ISLAND.

STEAM-ENGINE VALVEi SPECIFICATION forming part of Letters Patent No. 280,312,4 dated June 26, 18.83.`

Application filed January 5, 1.883. (No model.)

l ure of the steam on one valve or part is caused to balance that on a corresponding valve or part arranged opposite thereto. I will describe the invention as having only two valves or parts thus balanced, and as working within a chamber which is cylindrical 5 but there may be four or other desired number, and they may work within a chamber which is of rectangular or octagonal form in cross-section, if desired. I

` provide for delicately adjusting the conditions by means of a very slightly tapering wedge. arranged not to force apart but to draw together the valves or parts. When this wedge is too much Withdrawn` the steam forces the valves apart and causes them to press tightly on their respective seats. By forcing the wedge inward they are drawn together and the friction on the seats is relieved. I provide easy means for adjusting the wedge with great delicacy. It may be adjusted while the engine it running. I construct the parts so braced that they will avoid springing under the great strains to which they are subjected.

rIlhe accompanying drawings form a part of this specication, and represent what I consider the best means of carrying out the invention. v

Figure lis a central vertical section through the valve and its immediate connections. Fig. la represents the operating-yoke and adjusting-wedge detached. It is an elevation partly in section at right anglesv to the view in Fig. 1. w Fig. 2 is a horizontal section on the line vin Fig. l. Fig. 8 is a horizontal section on the line y y in Fig. 1. Fig. 4 is a horizontal se'e'tion on the line z z in Fig. 1. Fig. 5 represents a modification. It is ahorizontal section in a plane corresponding to x in Fig. l.

Similar letters of reference indicate like parts in all the gures.`

A is the main cylinder, invwhich works the main piston. (Not represented.) Parallel to this is-a peculiarly-constructed casing of castiron or other suitable material, which is cast -in 011e therewith or firmly bolted thereto, the

' cated through suitable valve-gear. (Not represented, but which may be the ordinary linkmotion.)

The valve-stein is marked B, certain portions w being designated, when necessary, by additional marks of reference, as B. The stem B is iinished round and smooth where it passes out through suitable stuffing-boxes. Its upper end is hollow, and receives a wedge, M,Which extends out through the upper end of the stem B, and is iinislled with a left-handed screwthread. The upper end of the stem B has a right-handed screw-thread.

C is a thumb-nut adapted to engage .both the left-hand screw-threads on M and the righthand screw-threads von B. By turning it one, way and the other the right and -left threads shift the wedge M up and down relatively to the stem B, while both B and M are actively reciprocated endwise, giving a corresponding motion to the valves D and E. The reciproeating motion is communicated to the latter by the square internal shoulders of the yoke B. The outer sides or faces of the valves D and E are accurately finished to match steam-tight against the interior of A. The parts D andv viE, which I will continue to term separzttey valves, although they work together as a single valve, are each formed with a stout rib, D E', of L-section, extending up and down` near the center of its back. The wedge M stands betweenthese ribs, as plainly indicated in Figs. 2, 3, and 4. The surface being finished so that the inclined sides ofthe longand-tapering wedge M apply fairly, one side` against the L part or hook part on the rib D andthe-other inclined side against the L part or hook part of the rib E.

Exterior, tothe cylindrical casing A is a" casing, A2,'which isapproximately cylindrical. The space between the inner shell, A',

IOO

and the outer shell, A5, is divided by three horizontal partitions. The upper one is marked A, the lowest one A, and the middle one A5. The space above A5, at the upper end, communicates with the upper end of the steam-cylinder A. The space below the bottom partition, A, communicates with the bottom of the main cylinder A. Two narrow ports are formed through the shell A', above the partition A5. Two similar ports are formed below the partition A4. The tight-fitting faces of the valves D and E are, by the action of the engine, communicated through the rod B and yoke B', moved alternately above and below these ports. The interior of each end of the inner shell, A', is kept lled with steam. The faces of D and E are hollow-throated, and receive the exhaust-steam from the ports and convey it away. The space between the partitions Av5 and A5 is kept filled with steam from the boiler. The space below A5 and between it and A4 is in free communication with the exhaust-pipe. The hollow throats of the valves D and E communicate with the space below A5 through ample passages a.. The spaces at the ends of the valves D and E, and the spaces between the latter surrounding the webs D E and. surrounding the yoke B and the wedge M, are supplied with steam from the space above A5 through an ample passage, a. (Shown in strong lines in Fig. 3 and in dotted lines in Fig. 1.) The pressure of the steam between the valves D and E tends to force them apart and to press each with great violence against its respective side of the interior of the shell A. This force is resisted by the wedge M engaging and fitting fairly against the continuous offsets or hooks of the respective parts D E.

,In starting the engine the iirst time it is well to have the wedge M rather too highly elep vated, so as to let the valves D and E bear too forcibly against their respective seats on the interior of the shell A. This involves great friction, but need be endured only a few strokes, the throttle-valve (not shown) being opened slightly, so as to give but a moderate pressure of steamv and induce only a slow movement of the engine. The nut C is turned by hand or v otherwise to force down the wedge M and haul both valves slightly away from their seats. A little practice shows, by following the sound, when the valves are just sufficiently lifted from their seats to make them go easily. throttle is opened wider, giving full pressure either suddenly or gradually, and if the wedge 'M requires any further adjustment up or down it is done. Then a jam-nut, Gf, is tightened up against C, and the valves are held as thus adjust steam-tight: contact with their seats. My experiments indi cate that the friction and wear. will be very slight. The great area of open! ing obtained is very desirable for quick-work! ing engines.

, The hollow throat of eachv valve D and Eis, formed with a straight tie across, as indicated'.

Then the by D2 E2. These greatly'stiffen thevalve andallow it 'to withstand ahigh pressure without changing its form. It is made with the openings, and especially with a liberal opening near each end, which allow the exhaust-steam to circulate freely. The construction affords very liberalpassages for the steam to traverse without wire-drawing.

Modifications may be made in the forms and proportions. I can make the inner casing, A', square instead of cylindrical. In such case the faces of the valves D and E would be plane, and would correspond in appearance as well as in function to the ordinary hollow-throated flat slide-valve.- I can employ more than two valves, D and E. I propose in large engines to employ four. Fig. 5 is an outline showing such modification. It is taken on a line corresponding to w x in Fig.'1. In such modification lthe ribs corresponding to D E cannot be continuous, but will be replaced by hooks which extend out at intervals'along the backs of the several valves and engage with the wedge M. The wedge M in such modification should taper-in both directions. In other words, it should have-no parallel faces such as are shown in Fig. 15, but both views of the wedge would show the tapered outline indicated in Fig. I. I have shown the four valves occupying so large aportion of the circumference that there is not so much space for the steam to fiow to each end from a central connection. I prefer to branch the steam-pipe (not shown) and lead a branch to each end ofthe casing. intervals, instead of continuous webs, may be employed when we have only two valves, D and E. In such case the wedge M may be taperedrapidly at the points where it is in contact with the hooks, and may have parallel surfaces or a form devoid of taper at the intermediate point.

I claim as my inventionl. The nut C, having right and left'hand threads, the wedge M, having one thread, and the sleeve B, having the other thread, corresponding with said threads in the nut C, in combination with each other and with the yoke B and valves D D E E', and securing means C, arranged .for joint operation relaspecified.

2. vIn a steanreiigine, the valves D and E, of .i large area, balanced, as shown, by each other,

V,and each formed with a hollow throat braced facross by a rigid tie, as D2 E2,'to avoid the springing of the metal under the strain, as

herein specified.

justed, balancing each other and moving with 3. In combination with the main cylinder,

yA of a steam-engine, -the casings A A2, ar-

'with valves DE, as and for the purposes herel 4in specified.

` 4. In combinatlon, the main cylinderA,

tparallel casing A, exterior casing A2," trans- IOO IIO

`tively to each other and to the stufling-boX 'around the sleeve B, substantially as herein `verse partitions A A4 A5, two or more separate valves, D E, with their engaging ribs or esom v 3 my hand, at Bristol, Rhode Island, this 28th day of December, 1882, in the presence yof two 1o hooks D E', Wedge M, yoked Valvestem B B', subscribing Witnesses.

and means, as C C', for adjusting and firmly 5 securing the-adjustment of the balancing force,

all arranged for joint operation as and for the purposes herein specified.

In testimonyT whereof I have hereunto set NATHL. G. HERRESHO'FF. 

